SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14f7b568953f1dbacd88902afca3c94ee4065b8a4578fe375248d12aeeeac562' 
  AND token = 'JofLwQuoDgLQqfU6Mz9fwwAcWPpt9KY1YK6z2KXCm+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}